Sacred Scripture begins with the creation and union of man and woman and ends with "the wedding feast of the Lamb" (Rev 19:7, 9). Scripture often refers to marriage, its origin and purpose, the meaning God gave to it, and its renewal in the covenant made by Jesus with his Church. Man and woman were created for each other.
By their marriage, the couple witnesses Christ's spousal love for the Church. One of the Nuptial Blessings in the liturgical celebration of marriage refers to this in saying, "Father, you have made the union of man and wife so holy a mystery that it symbolizes the marriage of Christ and his Church."
The Sacrament of Marriage is a covenant, which is more than a contract. Covenant always expresses a relationship between persons. The marriage covenant refers to the relationship between the husband and wife, a permanent union of persons capable of knowing and loving each other and God. The celebration of marriage is also a liturgical act, appropriately held in a public liturgy at church. Catholics are urged to celebrate their marriage within the Eucharistic Liturgy.
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No more shall men call you "Forsaken," or your land "Desolate," But you shall be called "My Delight," and your land "Espoused." For the LORD delights in you, and makes your land his spouse. 5 As a young man marries a virgin, your Builder shall marry you; And as a bridegroom rejoices in his bride so shall your God rejoice in you. (Isaiah 62: 4–5)
Pope Paul VI wrote: “By it [the Sacrament of Matrimony] husband and wife are strengthened and…consecrated for the faithful accomplishment of their proper duties, for the carrying out of their proper vocation even to perfection, and the Christian witness which is proper to them before the whole world” (Humanae Vitae, n. 25).